Updating the Smith Period for Improved Late Blight Management in the UK

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1 Updating the Smith Period for Improved Late Blight Management in the UK Siobhán Dancey Project Supervisors: Dr. Peter Skelsey & Dr. David Cooke

2 DSS in Britain Smith Period SMITH PERIOD (ca. 1950): At least two consecutive days where the temperature is at least 10 C and on each day there are at least 11 hours where the relative humidity is 90% or greater.

3 The Smith Period today Courtesy of E. Anderson, Scottish Agronomy Ltd.

4 Contemporary pathogen population

5 Re-Evaluating the Smith Period Three Stages 1. Historic Outbreak and Weather Data Analysis 2. Contemporary Isolate Investigation 3. Development of a UK based disease risk model for late blight

6 Historical Outbreak Data Year Sampled PLB Outbreaks Unique Postcodes Total Outbreaks: Unique Postcodes:

7 Historical Met Office Data 652 locations across Britain Data for: April 1 st September 30 th Everyday Correlates with outbreak regions

8 Historic Data Analysis The Met Office Data provides I. The minimum daily temperature II. The number of hours each day when the RH 90% Four Classifications 1. Near Criteria 2. Full Criteria 3. Near Period 4. Full Period Year Sampled PLB Outbreaks Unique PLB Postcodes Unique Met Office Squares Total Outbreaks: Unique Postcodes:

9 Initial Met Data Analysis 2003 Each outbreak was scored based on whether a Smith Period had been issued in the previous 30 days (if data available) Each year a large proportion of early outbreaks were not predicted by a Smith Period 2003: 30 Outbreaks between April- June 12 had a Smith Period Warning

Initial Met Data Analysis 2004 & 2005 2004:

10 Initial Met Data Analysis 2004 & : 14 Outbreaks between April- June 0 had a Smith Period Warning 2005: 23 Outbreaks between April- June 7 had a Smith Period Warning

11 Initial Met Data Analysis st 30 PLB Outbreaks April May June July % 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Smith Period Alert Given No Smith Period Alert Given

12 Historic Data Analysis Plan 1. Time series of all accumulated outbreaks each year with accumulating Smith Periods relationship? 2. First outbreaks of the year, why are we missing them? Temperature or humidity? 3. Examination of key potato growing areas and weather station locations compared to predicted outbreaks

13 Refining the Smith Period Criteria Contemporary Isolates of Phytophthora infestans from outbreak samples from 2012 and 2013 o 3 X 13_A2 o 3 X 6_A1 o 1 X 7_A1 o 1 X 8_A1

14 Refining the Smith Period Criteria

Detached Leaf Results Infection below 10 C at 100% RH for contemporary UK isolates

Infection of 13_A2 Isolates at 100% Relative Humidity 13_A2-7 C Infection (n/56)

13_A2-10 C 13_A2-11 C 13_A2-13 C 13_A2-15 C 0 3 4 5 Days Post Inoculation 6 7 8 9

15 Detached Leaf Results Infection below 10 C at 100% RH for contemporary UK isolates of P. infestans Infection of 6_A1 Isolates at 100% Relative Humidity 6_A1-7 C Infection of 13_A2 Isolates at 100% Relative Humidity 13_A2-7 C Infection (n/56) _A1-10 C 6_A1-11 C 6_A1-13 C 6_A1-15 C Infection (n/56) _A2-10 C 13_A2-11 C 13_A2-13 C 13_A2-15 C Days Post Inoculation _A1-7 C 6_A1-15 C 6_A1-11 C Days Post Inoculation _A2-11 C 13_A2-7 C 13_A2-15 C

16 Detached Leaf Results Infection below 90 % RH for contemporary UK isolates of P. infestans 6_A1 and 13_A2 P. Infestans Infection at 10 C and % RH 6_A1 and 13_A2 P. Infestans Infection at 14 C and % RH Percent Infection 80% 70% 60% 50% 40% 30% 20% 10% 0% 70% 80% 90% 100% 10 C 5 5 Days Post Inoculation % Relative Humidity 6_A1-24 Hours 6_A1-11 Hours 6_A1-6 Hours 13_A2-24 Hours 13_A2-11 Hours 13_A2-6 Hours Percent Infection % 80% 90% 100% 14 C 5 5 Days Post Inoculation % Relative Humidity 6_A1-24 Hours 6_A1-11 Hours 6_A1-6 Hours 13_A2-24 Hours 13_A2-11 Hours 13_A2-6 Hours

17 Expansion of Smith The Met Office provides warnings based on the UV index scale, it does not generally go above 8 in the UK Spore survival in UV Field and Lab Experiments o Canopy Levels o Dry Vs Wet

Further Work Further analysis of Met Office and Outbreak data Validation of new parameters with a larger selection of contemporary isolates and plantlets

18 Further Work Further analysis of Met Office and Outbreak data Validation of new parameters with a larger selection of contemporary isolates and plantlets Augmentation of the forecasting system UV Effect of high winds/ heavy rains Effect of neighbouring field infections Scaling Peter Skelsey s PLB simulator

19 Thank You for your time

20 2003 No Smith Period Smith Period No Smith Criteria Smith Criteria April May June July Total No Smith Period Smith Period No Smith Criteria Smith Criteria April May June July Total No Smith Period Smith Period No Smith Criteria Smith Criteria April May June July Total No Smith Period Smith Period No Smith Criteria Smith Criteria April May June July Total

The Hutton Criteria. Siobhán Roísín Dancey The James Hutton Institute Supervisors: Peter Skelsey, David Cooke. #AgConf16

The Hutton Criteria. Siobhán Roísín Dancey The James Hutton Institute Supervisors: Peter Skelsey, David Cooke. #AgConf16 The Hutton Criteria Siobhán Roísín Dancey The James Hutton Institute Supervisors: Peter Skelsey, David Cooke #AgConf16 The Smith Period The Beaumont Period: Two consecutive days where: 1. Each day has